Existing methods of constructing wind towers vary depending on whether the materials are steel or concrete. The decision process used to select whether the tower is to be built out of steel or concrete depends on the geographic location, regional resources, and access to the wind farm site. Steel wind towers are commonly built through bolting steel tubular sections together at intermediate flanges. The heights of steel towers are often limited by the diameter of the steel tubular sections that can be physically transported from the location where the steel pieces are fabricated to the wind farm site without significant modifications to existing roads, bridges, or other physical constraints. These limitations typically result in steel pieces having diameters of up to approximately 20.0 feet. As a result of these diameter limitations, the overall tower height is generally limited when using conventional strength steel. Energy production from a wind tower generally goes up by increasing the height of the tower. Thus, the transportation constraints limit the productivity of the windmill when the tower is made of conventional strength steel.
Advantages of concrete towers include that the concrete sections can be constructed using local materials. As a result, the concrete sections are not transported over long distances and the transportation constraints involved with transporting steel sections are avoided. Cast-in-place construction methods allow for pouring fresh concrete into the forms at any desired height. The drawbacks to cast-in-place methods are reduced construction speed and sensitivity to inclement weather. The common geometry of a concrete wind tower is tapered, which creates complexity in the concrete segment forming system.
One type of foundation for a tower is disclosed in U.S. Patent Publication No. 2014/0202971 issued to Eli Bosco. In this reference, an enhanced stability crane is described. Embodiments include a telescoping main support mast upon which a crane base resides. A boom projects upwardly from the crane base and a jib typically projects upwardly from the boom. A clamping assembly resides on the main support mast and is configured to attach to an existing structure adjacent to the crane, in order to enhance stability. Multiple clamping assemblies can be distributed along the telescoping main support mast when it is extended. The existing structure is generally a tower structure that is columnar and vertical in shape and orientation, and frequently has an elliptical horizontal cross-section. Tower structures are typically, but not necessarily, wind turbine towers. In some embodiments, the crane is mobile capable of lifting objects weighing about 110 tons to a height of about 400 feet. The crane typically adjusts to a collapsed configuration, enabling facile transport. U.S. Patent Publication No. 2014/0202971 is herein incorporated by reference for all that it contains.